Stand-alone expandable interbody spinal fusion device with locking mechanism

ABSTRACT

A stand-alone expandable interbody spinal fusion device, including a superior component, an inferior component, an expansion mechanism operatively arranged to displace the superior component in a first direction relative to the inferior component about a first hinge, and a locking mechanism. The locking mechanism including a plate operatively arranged to pivot about a second hinge, the plate further including a first through-bore and a first plurality of teeth, a pawl operatively arranged to pivot about a third hinge, the pawl further including a second through-bore, and a post operatively arranged to pass through the second and third through-bores such that after the superior component is displaced in the first direction, the locking mechanism prevents displacement of the superior component in a second direction, opposite the first direction.

FIELD

The disclosure relates to spinal surgery, more particularly tointervertebral prosthesis, and, even more specifically, to a stand-aloneexpandable interbody spinal fusion device with a locking mechanism.

BACKGROUND

The spinal column, or backbone, is one of the most important parts ofthe body. It provides the main support, allowing us to stand upright,bend, and twist. As shown in FIG. 1, thirty three (33) individual bonesinterlock with each other to form the spinal column. The vertebrae arenumbered and divided into regions. The cervical vertebrae (C1-C7) formthe neck, support the head and neck, and allow nodding and shaking ofthe head. The thoracic vertebrae (T1-T12) join with the ribs to form therib cage. The five lumbar vertebrae (L1-L5) carry most of the weight ofthe upper body and provide a stable center of gravity when a personmoves. Five vertebrae of the sacrum S and four of the coccyx C arefused. This comprises the back wall of the pelvis. Intervertebral discsare located between each of the mobile vertebra. Intervertebral discscomprise a thick outer layer with a crisscrossing fibrous structureannulus A that surrounds a soft gel-like center, the nucleus N. Discsfunction like shock-absorbing springs. The annulus pulls the vertebralbodies together against the elastic resistance of the gel-fillednucleus. When we bend, the nucleus acts like a ball bearing, allowingthe vertebral bodies to roll over the incompressible gel. Each discworks in concert with two facet joints, forming a spinal motion segment.The biomechanical function of each pair of facet joints is to guide andlimit the movement of the spinal motion segment. The surfaces of thejoint are coated with cartilage that helps each joint move smoothly.Directly behind the discs, the ring-like vertebral bodies create avertical tunnel called the spinal canal, or neuro canal. The spinal cordand spinal nerves pass through the spinal canal, which protects themfrom injury. The spinal cord is the major column of nerve tissue that isconnected to the brain and serves as an information super-highwaybetween the brain and the body. The nerves in the spinal cord branch offto form pairs of nerve roots that travel through the small openingsbetween the vertebrae and the intervertebral foramens.

The repetitive forces which act on these intervertebral discs duringrepetitive day-to-day activities of bending, lifting and twisting causethem to break down or degenerate over time. Overt trauma, or coverttrauma occurring in the course of repetitive activitiesdisproportionately affect the more highly mobile areas of the spine.Disruption of a disc's internal architecture leads to bulging,herniation or protrusion of pieces of the disc and eventual disc spacecollapse. Resulting mechanical and chemical irritation of surroundingneural elements cause pain, attended by varying degrees of disability.In addition, loss of disc space height relaxes tension on thelongitudinal ligaments, thereby contributing to varying degrees ofspinal instability such as spinal curvature.

Neural irritation and instability resulting from severe disc damage hasbeen treated by removing the damaged disc and fusing adjacent vertebralelements. Removal of the disc relieves the mechanical and chemicalirritation of neural elements, while osseous union solves the problem ofinstability. For example, in one surgical procedure, known as adiscectomy (or diskectomy) with interbody fusion, the surgeon removesthe nucleus of the disk and replaces it with an implant. As shown inFIG. 2, it may be necessary, for example, for the surgeon to remove thenucleus of the disc between the L3 and L4 vertebrae. Disc D_(L3-L4) isshown in an enlarged view in FIG. 3. This figure also shows variousanatomical structures of the spine, including facets F3A and F4A, facetjoint FJ, spinous processes SP3 and SP4, transverse processes TP3A andTP4A, and intervertebral foramen IF. FIG. 4 is a top view of the sectionof the spinal column shown in FIG. 3, with the L3 vertebra removed toexpose annulus A and nucleus N of disc D_(L3-L4). Neural canal NC isalso shown. FIG. 5 is an anterior perspective view of the section of thespinal column shown in FIG. 4. FIG. 6 is a partial cross-sectional viewof the section of the spinal column shown in FIG. 5, but with vertebraL3 in place atop disc D_(L3-L4).

While cancellous bone appears ideal to provide the biologic componentsnecessary for osseous union to occur, it does not initially have thestrength to resist the tremendous forces that may occur in theintervertebral disc space, nor does it have the capacity to adequatelystabilize the spine until long term bony union occurs. For thesereasons, many spinal surgeons have found that interbody fusion usingbone alone has an unacceptably high rate of bone graft migration or evenexpulsion or nonunion due to structural failure of the bone or residualdegrees of motion that retard or prohibit bony union.

Intervertebral prosthesis in various forms have therefore been used toprovide immediate stability and to protect and preserve an environmentthat fosters growth of grafted bone such that a structurally significantbony fusion can occur.

After insertion, and shortly after the conclusion of the surgicalprocess, these interbody devices experience the full weight of thepatient's upper body, originally experienced by the disc prior toreplacement. This weight may be sufficient to cause expandableintervertebral implants such as the implants disclosed in U.S. patentapplication Ser. No. 15/416,270 filed Jan. 26, 2017, which applicationis herein incorporated by reference in its entirety, to collapse fromits expanded state to its unexpanded height negatively affecting thequality of bone fusion.

Thus, there is a long-felt need for a stand-alone expandable interbodyspinal fusion device with a locking mechanism operatively arranged toprevent collapse of an interbody device after insertion.

SUMMARY

According to aspects illustrated herein, there is provided a stand-aloneexpandable interbody spinal fusion device including a superiorcomponent, an inferior component, an expansion mechanism operativelyarranged to displace the superior component in a first directionrelative to the inferior component about a first hinge, and, a lockingmechanism comprising. The locking mechanism including a plateoperatively arranged to pivot about a second hinge, the plate furthercomprising a first through-bore and a first plurality of teeth, a pawloperatively arranged to pivot about a third hinge, the pawl furthercomprising a second through-bore, and a post operatively arranged topass through the second and third through-bores such that after thesuperior component is displaced in the first direction, the lockingmechanism prevents displacement of the superior component in a seconddirection, opposite the first direction.

According to aspects illustrated herein, there is provided a stand-aloneexpandable interbody spinal fusion device including a superiorcomponent, an inferior component, an expansion mechanism operativelyarranged to displace the superior component in a first directionrelative to the inferior component about a hinge, and a lockingmechanism. The locking mechanism including a first plate fixedly securedto the superior component, the first plate further comprising a firstthrough-bore, a second plate fixedly secured to the inferior component,the second plate further comprising a second through-bore, a post havinga first end and a second end such that after the superior component isdisplaced in the first direction, the locking mechanism preventsdisplacement of the superior component in a second direction, oppositethe first direction.

According to aspects illustrated herein, there is provided a stand-aloneexpandable interbody spinal fusion device including a superiorcomponent, an inferior component, an expansion mechanism operativelyarranged to displace the superior component in a first directionrelative to the inferior component, and a locking mechanism. The lockingmechanism including a first plate fixedly secured to the superiorcomponent, the first plate further comprising a first through-bore, asecond plate fixedly secured to the inferior component, the second platefurther comprising a second through-bore, a third plate fixedly securedto the superior component, the third plate further comprising a thirdthrough-bore, a fourth plate fixedly secured to the inferior component,the fourth plate further comprising a fourth through-bore, and, a postarranged to engage with the first through-bore, the second through-bore,the third through-bore, and the fourth through-bore, such that after thesuperior component is displaced in the first direction, the lockingmechanism prevents displacement of the superior component in a seconddirection, opposite the first direction.

These and other objects, features, and advantages of the presentdisclosure will become readily apparent upon a review of the followingdetailed description of the disclosure, in view of the drawings andappended claims.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

Various embodiments are disclosed, by way of example only, withreference to the accompanying schematic drawings in which correspondingreference symbols indicate corresponding parts, in which:

FIG. 1 is an anterior perspective view of spinal column 10;

FIG. 2 is an anterior perspective view of the lumbar section of spinalcolumn 10;

FIG. 3 is a lateral perspective view of L3, L4 vertebrae and discD_(L3-L4) and related spinal anatomy;

FIG. 4 is a top view of a section of the spinal column, taken generallyalong line 4-4 in FIG. 3;

FIG. 5 is an enlarged anterior perspective view of the spinal columnshown in FIG. 2, except with vertebra L3 and all other structure aboveL3 removed;

FIG. 6 is a partial cross-sectional view of the L4 vertebra andD_(L3-L4) disc shown in FIG. 5, including L3 in cross-section;

FIG. 7 is a partial cross-sectional view of the L4 vertebra andD_(L3-L4) disc shown in FIG. 5, showing the removal of the disc nucleuspost-discectomy including L3 in cross-section;

FIG. 8 illustrates the introduction of the stand-alone expandableinterbody spinal fusion device into the disc space in an unexpandedstate;

FIG. 9 is a perspective view of a first embodiment of a stand-aloneexpandable interbody spinal fusion device, in an unexpanded state;

FIG. 10 is a partially-exploded perspective view of a stand-aloneexpandable interbody spinal fusion device with a first embodiment of alocking mechanism, in an expanded state;

FIG. 11 is a front view of a stand-alone expandable interbody spinalfusion device with a first embodiment of a locking mechanism, in anunexpanded state;

FIG. 12 is a cross-sectional view of a stand-alone expandable interbodyspinal fusion device with a first embodiment of a locking mechanism, inan unexpanded state, taken generally along line 12-12 in FIG. 11;

FIG. 13 is a front view of a stand-alone expandable interbody spinalfusion device with a first embodiment of a locking mechanism, in anexpanded state;

FIG. 14 is a cross-sectional view of a stand-alone expandable interbodyspinal fusion device with a first embodiment of a locking mechanism, inan expanded state, taken generally along line 14-14 in FIG. 13;

FIG. 15 is a perspective view of an expansion mechanism in an unexpandedstate;

FIG. 16 is a perspective view an expansion mechanism in an expandedstate;

FIG. 17 is a side view of a second embodiment of a locking mechanism;

FIG. 18 is a front perspective partially exploded view of a secondembodiment of a locking mechanism;

FIG. 19 is a front perspective view of a stand-alone expandableinterbody spinal fusion device with a second embodiment of a lockingmechanism, in an unexpanded state;

FIG. 20 is a front perspective view of a stand-alone expandableinterbody spinal fusion device with a second embodiment of a lockingmechanism, in an expanded state;

FIG. 21 is a side view of a third embodiment of a locking mechanism;

FIG. 22 is a front perspective partially exploded view of a thirdembodiment of a locking mechanism;

FIG. 23 is a front perspective view of a stand-alone expandableinterbody spinal fusion device with a third embodiment of a lockingmechanism, in an unexpanded state;

FIG. 24 is a front perspective view of a stand-alone expandableinterbody spinal fusion device with a third embodiment of a lockingmechanism, in an expanded state;

FIG. 25 is a front perspective partial view of a fourth lockingmechanism in an unlocked state;

FIG. 26 is a front perspective partial view of a fourth lockingmechanism in a locked state;

FIG. 27 is a front partially-exploded perspective view of a stand-aloneexpandable interbody spinal fusion device with a fourth embodiment of alocking mechanism in an unexpanded state;

FIG. 28 is a front perspective view of a stand-alone expandableinterbody spinal fusion device with a fourth embodiment of a lockingmechanism in an expanded state;

FIG. 29 is a front perspective partial view of a fifth locking mechanismin an unlocked state;

FIG. 30 is a front perspective partial view of a fifth locking mechanismin a locked state;

FIG. 31 is a front partially-exploded perspective view of a stand-aloneexpandable interbody spinal fusion device with a fifth embodiment of alocking mechanism in an unexpanded state;

FIG. 32 is a front partially-exploded perspective view of a stand-aloneexpandable interbody spinal fusion device with a fifth embodiment of alocking mechanism in an expanded state;

FIG. 33 is a perspective view of a sixth embodiment of a stand-aloneexpandable interbody spinal fusion device, in an unexpanded state;

FIG. 34 is a partially-exploded perspective view of a stand-aloneexpandable interbody spinal fusion device with a sixth embodiment of alocking mechanism, in an expanded state;

FIG. 35 is a front view of a stand-alone expandable interbody spinalfusion device with a sixth embodiment of a locking mechanism, in anunexpanded state;

FIG. 36 is a cross-sectional view of a stand-alone expandable interbodyspinal fusion device with a sixth embodiment of a locking mechanism, inan unexpanded state, taken generally along line 36-36 in FIG. 35;

FIG. 37 is a front view of a stand-alone expandable interbody spinalfusion device with a sixth embodiment of a locking mechanism, in anexpanded state;

FIG. 38 is a cross-sectional view of a stand-alone expandable interbodyspinal fusion device with a sixth embodiment of a locking mechanism, inan expanded state, taken generally along line 38-38 in FIG. 37;

FIG. 39 is a front perspective partial view of a seventh embodiment of alocking mechanism in an unlocked state;

FIG. 40 is a front perspective partial view of a seventh embodiment of alocking mechanism in a locked state;

FIG. 41 is a front partially-exploded perspective view of a stand-aloneexpandable interbody spinal fusion device with a seventh embodiment of alocking mechanism in an unexpanded state;

FIG. 42 is a front perspective view of a stand-alone expandableinterbody spinal fusion device with a seventh embodiment of a lockingmechanism in an expanded state;

FIG. 43 is a front perspective partial view of an eighth embodiment of alocking mechanism in an unlocked state;

FIG. 44 is a front perspective partial view of an eighth embodiment of alocking mechanism in a locked state;

FIG. 45 is a front partially-exploded perspective view of a stand-aloneexpandable interbody spinal fusion device with an eighth embodiment of alocking mechanism in an unexpanded state;

FIG. 46 is a front perspective view of a stand-alone expandableinterbody spinal fusion device with an eighth embodiment of a lockingmechanism in an expanded state.

DETAILED DESCRIPTION OF EMBODIMENTS

At the outset, it should be appreciated that like drawing numbers ondifferent drawing views identify identical, or functionally similar,structural elements. It is to be understood that the claims are notlimited to the disclosed aspects.

Furthermore, it is understood that this disclosure is not limited to theparticular methodology, materials and modifications described and assuch may, of course, vary. It is also understood that the terminologyused herein is for the purpose of describing particular aspects only,and is not intended to limit the scope of the claims.

Unless defined otherwise, all technical and scientific terms used hereinhave the same meaning as commonly understood to one of ordinary skill inthe art to which this disclosure pertains. It should be understood thatany methods, devices or materials similar or equivalent to thosedescribed herein can be used in the practice or testing of the exampleembodiments. The assembly of the present disclosure could be driven byhydraulics, electronics, and/or pneumatics. It should be appreciatedthat the term “substantially” is synonymous with terms such as “nearly,”“very nearly,” “about,” “approximately,” “around,” “bordering on,”“close to,” “essentially,” “in the neighborhood of,” “in the vicinityof,” etc., and such terms may be used interchangeably as appearing inthe specification and claims. It should be appreciated that the term“proximate” is synonymous with terms such as “nearby,” “close,”“adjacent,” “neighboring,” “immediate,” “adjoining,” etc., and suchterms may be used interchangeably as appearing in the specification andclaims. The term “approximately” is intended to mean values within tenpercent of the specified value.

The term “Superior Component” as used in the present disclosure isintended to mean the component of the body of the implant located in thehighest position relative to the other components in first directionDR1.

The term “Inferior Component” as used in the present disclosure isintended to mean the component of the body of the implant located in thelowest position relative to the other components in first direction DR1.

The term “gear shaft” as used in the present disclosure is intended tomean any gear currently understood in the art that has been elongatedsuch that it is substantially cylindrical in shape.

The term “pawl” as used in the present disclosure is intended to mean aplate or bar having one end arranged to engage the teeth of a ratchetand place pressure on the ratchet in a first direction such that theratchet can only be disengaged from the teeth by motion in a seconddirection, opposite the first direction.

Adverting now to the Figures, and as described previously, FIGS. 1-6depict various parts and sections of spinal anatomy. FIG. 7 illustratesa partial cross-sectional view of the L3 and L4 vertebra with discD_(L3-L4) removed (post discectomy) and able to receive stand-aloneexpandable interbody spinal fusion device 100.

FIG. 8 illustrates a partial cross-sectional view of the L3 and L4vertebra with stand-alone expandable interbody spinal fusion device 100in place within disc space 12 in an unexpanded state.

FIG. 9 is a perspective view of stand-alone expandable interbody spinalfusion device 100, in an unexpanded state. Device 100 comprises superiorcomponent 102, inferior component 104, and expansion mechanisms 106,108, and 110 (described infra) arranged to displace superior component102 in a first direction DR1 relative to inferior component 104, givingdevice 100 an expanded height H₂ greater than unexpanded height H₁(shown in FIGS. 11 and 13). Device 100 also comprises locking mechanisms112, 114, 116, and 118 arranged between superior component 102 andinferior component 104 (locking mechanisms 116 and 118 are shown in FIG.10).

Locking mechanism 112 comprises plates 120A (shown in FIGS. 9) and 120B(shown in FIG. 10). Locking mechanism 114 comprises plates 120C (shownin FIGS. 9) and 120D (shown in FIG. 10). Locking mechanism 116 comprisesplates 120E (shown in FIGS. 9) and 120F (shown in FIG. 10). Lockingmechanism 118 comprises plates 120G (shown in FIGS. 9) and 120H (shownin FIG. 10). Each of plates 120A-120H further include a plurality ofthrough-bores, i.e., plurality of through-bores 122A-122H, respectively.It should be appreciated that, although plates 120A-120H are shown asintegral within superior component 102 and inferior component 104,plates 120A-120H could also be discrete plates, fixedly secured tosuperior component 102 and inferior component 104.

Superior component 102 and inferior component 104 further comprise atleast one first aperture 124 arranged to allow fusion between bonefusing material and the adjacent vertebra and a second aperture 126located on the front face of device 100 and arranged to allow theintroduction of bone fusing material into device 100. Second aperture126 is illustrated as an arched slot as a non-limiting example, however,it should be appreciated that second aperture 126 could be an apertureof any suitable shape, e.g., triangular, circular, rectangular,elliptical, etc., that would allow for the introduction of bone fusingmaterial into device 100. Superior component 102 has a first surface 103and inferior component 104 has a first surface 105.

FIG. 10 is a perspective view of stand-alone expandable interbody spinalfusion device 100, in an expanded state. It should be appreciated thatFIG. 10 is a partial view, i.e., superior component 102 has been removedfor clarity. During surgery and after device 100 is implanted in discspace 12, a surgeon can apply torque to expansion mechanisms 106, 108,and 110 via any device that imparts rotational force upon expansionmechanisms 106, 108, and 110 (e.g., a screw driver or impact driver).Expansion mechanisms 106, 108 and 110 are preferably the embodimentillustrated in FIGS. 15 and 16, described infra. Furthermore, it shouldbe appreciated that although expansion mechanisms 106, 108, and 110 aredepicted within inferior component 104 in FIGS. 9-14, expansionmechanisms 106, 108, and 110 could be arranged within superior component102. This rotational force causes expansion mechanisms 106, 108, and110, to displace superior component 102 in direction DR1 relative toinferior component 104 giving device 100 an expanded height H₂, greaterthan H₁ (shown in FIGS. 11 and 13). It should be appreciated thatexpansion mechanisms 106, 108, and 110, can be expanded to any heightbetween unexpanded height H₁ and expanded height H₂. Device 100 furthercomprises post 128 and fastener 130. Post 128 and fastener 130 areprovided to secure locking mechanisms 112 and 116 in position oncedevice 100 is expanded to its final height. Fastener 130 has a first end132 and a second end 134. First end 132 is operatively arranged toengage with any device known in the art that can impart rotationalmotion onto fastener 130, e.g., a drill. Second end 134 includes femalethreading 136. Post 128 further includes four sections, i.e., section138, section 140, section 142, and section 144. Section 138 comprisesmale threading 146 operatively arranged to engage with female threading136. Section 144 comprises stopping element 148. It should beappreciated that, although stopping element 148 is depicted as a flangedmember, other variations of stopping elements can be used, e.g., aspherical stopping element. Sections 138 and 142 have diameter D1 andsections 140 and 144 have diameter D2, where D2 is greater than D1.Prior to locking, sections 138 and 142 having diameter D1 are looselyseated in longitudinal space 150 (shown in FIG. 11) arranged betweeneach through-bore in the plurality of through-bores 122A, 122B, 122E,and 122F. After device 100 has been inserted into disc space 12 andexpanded to an appropriate height, a surgeon can apply torque to firstend 132 of fastener 130, pulling post 128 in direction DR3 into thelocked position. In the locked position, sections 140 and 144 arecompletely seated in one of the through-bores of plurality ofthrough-bores 122A, 122B, 122E, and 122F, which correspond to the chosendevice height. In this locked position, device 100 is prevented fromcollapsing in direction DR2.

Device 100 further comprises post 152 and fastener 154 (shown in FIG.14). Post 152 and fastener 154 are provided to secure locking mechanisms114 and 118 in position once device 100 is expanded to its final height.Fastener 154 has a first end 156 and a second end 158. First end 156includes a recess operatively arranged to engage with any device knownin the art that can impart rotational motion onto fastener 154, e.g., adrill. Second end 158 includes female threading 160. Post 152 includesfour sections, i.e., section 162, section 164, section 166, and section168. Section 162 comprises male threading 170 operatively arranged toengage with female threading 160 of fastener 154. Section 168 comprisesstopping element 172. It should be appreciated that, although stoppingelement 172 is depicted as a flanged member, other variations ofstopping elements can be used, e.g., a spherical stopping element.Sections 162 and 166 have diameter D1 and sections 164 and 168 havediameter D2 where D2 is greater than D1. Prior to locking, sections 162and 166, having diameter D1, are loosely seated in longitudinal space174 (shown in FIG. 11) arranged between each through-bore in theplurality of through-bores 122C, 122D, 122G, and 122H. After device 100has been inserted into disc space 12 and expanded to an appropriateheight, a surgeon can apply torque to first end 156 of fastener 154,pulling post 152 in direction DR3 into the locked position. In thelocked position, sections 164 and 168 are seated in one of thethrough-bores of plurality of through-bores 122C, 122D, 122G, and 122H,which corresponds to the chosen device height. In this locked position,device 100 is prevented from collapsing in direction DR2.

FIG. 11 is a front view of stand-alone expandable interbody spinalfusion device 100, in an unexpanded state having an unexpanded heightH₁. FIG. 12 is a cross-sectional view of stand-alone expandableinterbody spinal fusion device 100, in an unexpanded state having anunexpanded height H₁. FIG. 13 is a front view stand-alone expandableinterbody spinal fusion device 100, in an expanded state having anexpanded height H₂, greater than H₁. FIG. 14 is a cross-sectional viewof stand-alone expandable interbody spinal fusion device 100 in anexpanded state having an expanded height H₂, greater than H₁. It shouldbe appreciated that in FIGS. 12 and 14, expansion mechanisms 106, 108and 110 have been removed for clarity. It should also be appreciatedthat, although pluralities of through-bores 122A-122H are illustratedwith a longitudinal space between each through-bore of each plurality ofthrough-bores, it is also contemplated that plurality of through-bores122A-122H could include multiple discrete through-bores, separate anddistinct from each other with no longitudinal space between them.

FIG. 15 is a perspective view of expansion mechanism 176 in anunexpanded state. Expansion mechanism 176 comprises threaded rod 178,threaded sleeve 180, and worm drive 182 having worm 184 and gear 186. Aportion of threaded rod 178 can be embedded within superior component102 such that it is rotationally fixed; however, it should beappreciated that the frictional engagement between the top surface ofthreaded rod 178 and the inner surface of superior component 102 may besufficient to prevent threaded rod 178 from freely rotating. Duringsurgery and after device 100 is implanted in disc space 12, a surgeoncan apply torque to worm drive 182 via any device that impartsrotational force upon worm 184 (e.g., a screw driver or impact driver).Torque is transferred 90 degrees through worm drive 182, via worm 184and gear 186. Rotation of gear 186 causes threaded sleeve 180 to rotate.As threaded sleeve 180 rotates, threaded rod 178 remains rotationallylocked due to the portion embedded within superior component 102, orfrictional contact with the inner surface of superior component 102. Asthreaded sleeve 180 rotates, the threads of the rotationally lockedthreaded rod 178 ride upward along the threads within threaded sleeve180, displacing threaded rod 178, and subsequently superior component102, in direction DR1. Threaded rod 178 includes a stopping feature toprevent threaded rod 178 from being ejected from threaded sleeve 180.For example, the lower portion of threaded rod 178 could be threadless(not shown in the figures), and therefore prevent threaded rod 178 frombeing ejected from threaded sleeve 180. When threaded rod 178 reachesits maximum expansion, the unthreaded portion of threaded rod 178remains within threaded sleeve 180, preventing threaded rod 178 frombeing pushed out of threaded sleeve 180. Alternatively, the stoppingfeature could be a flange on the recessed portion of threaded rod 178arranged to engage with a retention shoulder (not shown in the figures)within threaded sleeve 180 in a fully expanded state. It should beappreciated that worm drive 182 could be arranged to transfer torque inother arrangements, i.e., 180 degrees, 270 degrees, or any desirableangle required by the arrangement of worm 184 and gear 186. It shouldfurther be appreciated that although a gear 186 is depicted in thefigures as a spur gear, other suitable gears may be selected, i.e., abevel gear, a hypoid gear, a spiral gear, or a face gear. FIG. 16 is aperspective view of an expansion mechanism 176 in an expanded state.

FIG. 17 is a side view of locking mechanism 220. Locking mechanism 220comprises plate 222, pawl 224, biasing element 226, post 228, andfastener 230. Plate 222 includes first surface 232, second surface 234,corner 236, hinge 238, and through-bore 240 operatively arranged toreceive post 228 and fastener 230. When in the locked position, corner236 abuts superior component 102 to stop superior component 102 frombeing displaced in direction DR2. Second surface 234 comprises firstplurality of teeth 242 and second plurality of teeth 244. Pawl 224includes through-bore 246, first pawl head 248, second pawl head 250,and hinge 252. Through-bore 246 is operatively arranged to accept post228. First and second pawl heads 248 and 250 taper to a point and areoperatively arranged to engage with first and second plurality of teeth242 and 244, respectively, on second surface 234 of plate 222. Prior tolocking, plate 222 and pawl 224 are freely pivotable about hinges 238and 252, respectively. Hinges 238 and 252 are pivotably secured to firstprotrusion 254 and second protrusion 256 of inferior component 204(discussed infra), respectively. It should be appreciated that althoughhinges 238 and 252 are illustrated as pivotably secured to firstprotrusion 254 and second protrusion 256, respectively, hinges 238 and252 could also be placed in a recess within inferior component 204.Biasing element 226 is fixedly secured between inferior component 204and pawl 224 and provides spring bias to pawl 224 in direction DR1and/or DR4. It should be appreciated that, although biasing element 226is depicted in FIGS. 17-20 as a flat spring, other biasing elementsknown in the art can be used to bias pawl 224 in direction DR1. Post 228includes first end 258 and second end 260. First end 258 includes malethreading 262, and second end 260 includes a stopping element 264. Itshould be appreciated that, although stopping element 264 is depicted asa spherical member, other variations of stopping elements can be used,e.g., a flanged stopping element. Fastener 230 includes first end 266and second end 268. First end 266 is operatively arranged to engage withany device known in the art that can impart rotational motion ontofastener 230, e.g., a drill. Second end 268 includes female threading270 operatively arranged to engage with male threading 262 of post 228.

After device 200 has been inserted into disc space 12 and expanded to anappropriate height, a surgeon can apply torque to first end 266 offastener 230, pulling post 228 in direction DR3. As post 228 is pulledin direction DR3, stopping element 264 of post 228 forces pawl 224 indirection DR3 against biasing element 226 about hinge 252. Whensufficient force is applied, first and second pawl heads 248 and 250,respectively, engage with first and second plurality of teeth 242 and244 locking the plate 222 in place and preventing the collapse of device200 (shown in FIGS. 19 and 20) in direction DR2.

FIG. 19 is a front perspective view of device 200 having two lockingmechanisms 214 and 216 in an unexpanded state. It should be appreciatedthat in an example embodiment locking mechanisms 214 and 216 areembodied as locking mechanism 220 discussed supra. Device 200 comprisessuperior component 202, inferior component 204, and expansion mechanism210 arranged to displace superior component 202 in first direction DR1relative to inferior component 204. Superior component 202 and inferiorcomponent 204 further comprise at least one first aperture 206 and atleast one second aperture 208, respectively, which are arranged to allowfusion between bone fusing material and the adjacent vertebra. Superiorcomponent 202 has a first surface 203 and inferior component 204 has afirst surface 205. Device 200 further comprises hinge 212 fixedlysecured to superior component 202 and inferior component 204 andarranged to rotatably displace the superior component about axis ofrotation AR. Expansion mechanism 210 is preferably expansion mechanism176 described supra. Although FIGS. 19 and 20 depict expansion mechanism210 fixedly secured within inferior component 204, it should beappreciated that expansion mechanism 210 could also be fixedly securedwithin superior component 202.

FIG. 20 is a front perspective view of device 200 having lockingmechanisms 214 and 216 in an expanded state. After superior component202 is displaced about axis of rotation AR, locking mechanisms 214 and216 are engaged and locked as discussed supra. Once locked, superiorcomponent 202 is prevented from moving in direction DR2.

FIG. 21 is a side view of locking mechanism 320. Locking mechanism 320comprises plate 322, post 324, and fastener 326. Plate 322 includescorner 328, hinge 330, and plurality of through-bores 332 operativelyarranged to receive post 324 and fastener 326. When in the lockedposition, corner 328 abuts superior component 102 to stop superiorcomponent 102 from being displaced in direction DR2. Post 324 includesfirst end 336 and second end 338. First end 336 includes male threading340, and second end 338 includes hinge 342. Plurality of through-bores332 (illustrated in FIG. 22) further includes longitudinal space 334arranged to receive first end 336 of post 324. Before locking, plate 322and post 324 are freely pivotable about hinges 330 and 342,respectively, and first end 336 of post 324 moves freely withinlongitudinal space 334 (shown in FIG. 22) of plurality of through-bores332. Hinges 330 and 342 are pivotably secured to first protrusion 344and second protrusion 346, respectively, of inferior component 302(discussed infra). It should be appreciated that although hinges 330 and342 are illustrated as pivotably secured to first protrusion 344 andsecond protrusion 346, respectively, hinges 330 and 342 could also beplaced in a recess within inferior component 304. Fastener 326 includesfirst end 348, second end 350, and flange 352. First end 348 isoperatively arranged to engage with any device known in the art that canimpart rotational motion onto fastener 326, e.g., a drill. Second end350 includes female threading 354 operatively arranged to engage withmale threading 340 of post 324. Flange 352 has diameter D1, and isoperatively arranged abut against the surface of plate 322 when secondend 350 is seated within one of plurality of through-bores 332 of plate322.

After device 300 (shown in FIGS. 23 and 24) has been inserted into discspace 12 and expanded to an appropriate height, a surgeon can applytorque to first end 348 of fastener 326, pulling fastener 326 indirection DR4. As fastener 326 is pulled in direction DR4, flange 352also moves in direction DR4 until flange 352 abuts the surface of plate322 while second end 350 of fastener 326 is seated within one ofplurality of through-bores 332 of plate 322 locking plate 322 in placeand preventing the collapse of device 300 (shown in FIGS. 23 and 24) indirection DR2.

FIG. 23 is a front perspective view of device 300 with lockingmechanisms 314 and 316, in an unexpanded state. It should be appreciatedthat in an example embodiment, locking mechanisms 314 and 316 areembodied as locking mechanism 320 discussed supra. Device 300 comprisessuperior component 302, inferior component 304, and expansion mechanism310 arranged to displace superior component 302 in a first direction DR1relative to inferior component 304. Superior component 302 and inferiorcomponent 304 further comprise at least one first aperture 306 and atleast one second aperture 308, respectively, which arranged to allowfusion between bone fusing material and the adjacent vertebra. Superiorcomponent 302 has a first surface 303 and inferior component 304 has afirst surface 305. Device 300 further comprises hinge 312 fixedlysecured to superior component 302 and inferior component 304 andarranged to rotatably displace the superior component about axis ofrotation AR. Although, FIGS. 23 and 24 depict expansion mechanism 310fixedly secured within inferior component 304, it should be appreciatedthat expansion mechanism 310 could also be fixedly secured withinsuperior component 302.

FIG. 24 is a front perspective view device 300 with locking mechanisms314 and 316, in an expanded state. After superior component 302 isdisplaced about axis of rotation AR, locking mechanisms 314 and 316 areengaged and locked as discussed supra. Once locked, superior component302 is prevented from moving in direction DR2.

FIG. 25 is a partial front perspective view of a locking mechanism 420in an unlocked state. Locking mechanism 420 comprises plates 422 and424, post 426, and fastener 428. Plates 422 and 424 are fixedly securedto superior component 402 and inferior component 404 (discussed infra),respectively. Plates 422 and 424 include first plurality ofthrough-bores 430 and second plurality of through-bores 432,respectively. First plurality of through-bores 430 and second pluralityof through-bores 432, which have diameter D2, less than diameter D3, andgreater than diameter D1. First plurality of through-bores 430 andsecond plurality of through-bores 432 are operatively arranged toreceive post 426 and fastener 428. First plurality of through-bores 430includes longitudinal space 434, and second plurality of through-bores432 includes longitudinal space 436. Post 426 includes a first end 438and a second end 440. First end 438 has diameter D1 and includes malethreading 442, and second end 440 includes shoulder 444 and stoppingelement 446. Shoulder 444 has diameter D2 and is operatively arranged toengage with first plurality of through-bores 430. Fastener 428 includesfirst end 448 and second end 450. First end 448 has diameter D3 (shownin FIG. 26) and is operatively arranged to engage with any device knownin the art that can impart rotational motion onto fastener 428, e.g., adrill. Second end 450 has diameter D2 and includes female threading 452operatively arranged to engage with male threading 442 of post 426.

Before locking, post 426 is freely moveable within longitudinal spaces434 and 436. During surgery, and after device 400 (discussed infra) hasbeen expanded to its final height, a surgeon imparts rotational motionto fastener 428. Female threading 452 of fastener 428 engages with malethreading 442 of post 426 pulling post 426 in direction DR3. Post 426 ispulled in direction DR3 until shoulder 444 engages one of thethrough-bores of first plurality of through-bores 430 and second end 450of fastener 428 engages one of the through-bores of the second pluralityof through-bores 432. When both second end 450 of fastener 428 andshoulder 444 of post 426 are engaged with the respective through-bores,device 400 is locked and is prevented from collapsing in direction DR2.It should be appreciated that, although not depicted in the figures, itis possible for shoulder 444 or second end 450 of fastener 428 to engagewith both the first plurality of through-bores 430 and second pluralityof through-bores 432 simultaneously. FIG. 26 is a partial frontperspective view of a locking mechanism 420 in a locked state. Whendevice 400 is in the fully collapsed state plates 422 and 424 nestwithin recesses 418.

FIG. 27 is a front perspective view of device 400 with lockingmechanisms 414 and 416, in an unexpanded state. Device 400 comprisessuperior component 402, inferior component 404, and expansion mechanism410 arranged to displace superior component 402 in a first direction DR1relative to inferior component 404. Superior component 402 and inferiorcomponent 404 further comprise at least one first aperture 406 and atleast one second aperture 408, which are arranged to allow fusionbetween bone fusing material and the adjacent vertebra. Superiorcomponent 402 has a first surface 403 and inferior component 404 has afirst surface 405. Device 400 further comprises hinge 412 fixedlysecured to superior component 402 and inferior component 404 andarranged to rotatably displace the superior component about axis ofrotation AR. Locking mechanisms 414 and 416 are preferably lockingmechanism 420 described supra. Expansion mechanism 410 is preferablyexpansion mechanism 176 described supra. It should be noted that sinceplates 422 and 424 are fixedly secured to superior and inferiorcomponents 102 and 104, respectively, recesses 418 are provided withinwhich plates 422 and 424 can nest while device 400 is in a collapsedstate. It should further be appreciated that plates 422 and 424 can behingedly secured to superior component 402 and inferior component 404,respectively. FIG. 28 is a front perspective view of device 400 withlocking mechanisms 414 and 416 in an expanded state.

FIG. 29 is a partial front perspective view of a locking mechanism 520in an unlocked state. Locking mechanism 520 comprises plates 522 and524, and fastener 426. Plates 522 and 524 are fixedly secured tosuperior component 502 and inferior component 504 (discussed infra),respectively. Plate 522 includes first plurality of through-bores 530and plate 524 includes second plurality of through-bores 532. Eachthrough-bore of first plurality of through-bores 530 has diameter D2.Each through-bore of the second plurality of through-bores 532 hasdiameter D1 larger than D2. First plurality of through-bores 530 andsecond plurality of through-bores 532 are operatively arranged tofastener 526. Second plurality of through-bores 532 further includeslongitudinal space 534. Fastener 526 includes first end 540 and secondend 542. First end 540 has diameter D2 and is operatively arranged toengage with any device known in the art that can impart rotationalmotion onto fastener 526, e.g., a drill. Second end 542 has diameter D1and includes male threading 544 operatively arranged to engage with anyof the through-bores of first plurality of through-bores 530.

Before locking, fastener 526 is freely moveable within longitudinalspace 534. During surgery, and after device 500 (discussed infra) hasbeen expanded to its final height, a surgeon imparts rotational motionto fastener 526. Male threading 544 of fastener 526 engages any of thethrough-bores of first plurality of through-bores 530 which pullsfastener 526 in direction DR4. When first end 540 of fastener 526 isengaged with second plurality of through-bores 532 and second end 542 isengaged with first plurality of through-bores 530, device 500 is lockedand is prevented from collapsing in direction DR2. FIG. 30 is a partialfront perspective view of a locking mechanism 520 in a locked state.When device 500 is in the fully collapsed state plates 522 and 524 nestwithin recesses 518.

FIG. 31 is a front perspective view of device 500 with lockingmechanisms 514 and 516, in an unexpanded state. Device 500 comprisessuperior component 502, inferior component 504, and expansion mechanism510 arranged to displace superior component 502 in a first direction DR1relative to inferior component 504. Superior component 502 and inferiorcomponent 504 further comprise at least one first aperture 506 and atleast one second aperture 508, which are arranged to allow fusionbetween bone fusing material and the adjacent vertebra. Superiorcomponent 502 has a first surface 503 and inferior component 504 has afirst surface 505. Device 500 further comprises hinge 512 fixedlysecured to superior component 502 and inferior component 504 andarranged to rotatably displace the superior component about axis ofrotation AR. Locking mechanisms 514 and 516 are preferably lockingmechanism 520 described supra. Expansion mechanism 510 is preferablyexpansion mechanism 176 described supra. It should be noted that sinceplates 522 and 524 are fixedly secured to superior and inferiorcomponents 502 and 504, respectively, recesses 518 are provided withinwhich plates 522 and 524 can nest while device 500 is in a collapsedstate. It should further be appreciated that plates 522 and 524 can behingedly secured to superior component 502 and inferior component 504,respectively. FIG. 32 is a front perspective view of device 500 withlocking mechanisms 514 and 516 in an expanded state.

FIG. 33 is a perspective view of stand-alone expandable interbody spinalfusion device 600, in an unexpanded state. Device 600 comprises superiorcomponent 602, inferior component 604, and expansion mechanisms 606,608, and 610 (described infra) arranged to displace superior component602 in a first direction DR1 relative to inferior component 604, givingdevice 600 an expanded height H₂ greater than unexpanded height H₁(shown in FIGS. 37 and 38). Device 600 also comprises locking mechanisms612, 614, 616, and 618 arranged between superior component 602 andinferior component 604.

Locking mechanism 612 comprises plate 620A (shown in FIGS. 33) and 620B(shown in FIG. 34). Locking mechanism 614 comprises plates 620C (shownin FIGS. 33) and 620D (shown in FIG. 34). Locking mechanism 616comprises plates 620E (shown in FIGS. 33) and 620F (shown in FIG. 34).Locking mechanism 618 comprises plates 620G (shown in FIGS. 33) and 620H(shown in FIG. 34). Plates 620A and 620C further include through-bores622A and 622C, respectively. Plates 620E and 620G further comprisesquare through-bores 622E and 622G, respectively. Plates 620B, 620D,620F, and 620H further comprise a plurality of through-bores, i.e.,plurality of through-bores 622B, 622D, 622F, and 622H, respectively. Itshould be appreciated that, although plates 620A-620H are shown asintegral within superior component 602 and inferior component 604,plates 620A-620H could also be discrete plates, fixedly secured tosuperior component 602 and inferior component 604.

Superior component 602 and inferior component 604 further comprise atleast one first aperture 624 arranged to allow fusion between bonefusing material and the adjacent vertebra and a second aperture 626located on the front face of device 600 and arranged to allow theintroduction of bone fusing material into device 600. Second aperture626 is illustrated as an arched slot as a non-limiting example, however,it should be appreciated that second aperture 626 could be an apertureof any suitable shape, e.g., triangular, circular, rectangular,elliptical, etc., that would allow for the introduction of bone fusingmaterial into device 600. Superior component 602 has a first surface 603and inferior component 604 has a first surface 605.

FIG. 34 is a perspective view of stand-alone expandable interbody spinalfusion device 600, in an expanded state. It should be appreciated thatFIG. 34 is a partial view, i.e., superior component 602 has been removedfor clarity. During surgery and after device 600 is implanted in discspace 12, a surgeon can apply torque to expansion mechanisms 606, 608,and 610 via any device that imparts rotational force upon expansionmechanisms 606, 608, and 610 (e.g., a screw driver or impact driver).Expansion mechanisms 606, 608 and 610 are preferably the embodimentillustrated in FIGS. 15 and 16, described supra. Furthermore, it shouldbe appreciated that although expansion mechanisms 606, 608, and 610 aredepicted within inferior component 604 in FIGS. 33-38, expansionmechanisms 606, 608, and 610 could be arranged within superior component602. The rotational force causes expansion mechanisms 606, 608, and 610,to displace superior component 602 in direction DR1 relative to inferiorcomponent 604 giving device 600 an expanded height H₂, greater than H₁(shown in FIGS. 37 and 38). It should be appreciated that expansionmechanisms 606, 608, and 610, can be expanded to any height betweenunexpanded height H₁ and expanded height H₂. Device 600 furthercomprises post 628. Post 628 is provided to secure locking mechanisms612 and 616 in position once device 600 is expanded to its final height.Post 628 comprises first section 638, second section 640, third section642, and fourth section 644. First section 638 has a first end 632, asecond end 634, and a flange 636. First end 632 is operatively arrangedto engage with any device known in the art that can impart rotationalmotion onto first section 638, e.g., a drill. Second end 634 is arrangednon-rotatably secure to second section 640. Second section 640 includesexternal helical male threading 646. Third section 642 includes asubstantially hollow shaft with cavity 650. Cavity 650 includes internalhelical female threading 651 operatively arranged to engage with malethreading 646. Fourth section 644 includes cylindrical portion 647non-rotatably secured to third section 642; and, stopping element 648which is embodied as a substantially rectangular member operativelyarranged to abut the surface of plate 620F and prevent movement of post628 in direction DR3. Second section 640 has a diameter D1. Thirdsection 642 has diameter D2 larger than D1. Cylindrical portion 647 offourth section 644 has diameter D3 larger than D2, and stopping element648 has diameter D4 larger than D3. Flange 636 has diameter D4 largerthan D3.

Prior to locking, first end 632 of first section 638 is slidinglyengaged with through-bore 622A (shown in FIG. 33); second section 640 isloosely seated in the longitudinal space formed between eachthrough-bore of plurality of through-bores 622B of plate 620B; thirdsection 642 is loosely seated in the longitudinal space formed betweeneach through-bore of plurality of through-bores 622F of plate 620F; andcylindrical portion 647 of fourth section 644 is slidingly engaged withsquare through-bore 622E of plate 620E.

After device 600 has been inserted into disc space 12 and expanded to anappropriate height, a surgeon can apply torque to first end 632 of firstsection 638. The torque is then transferred to second section 640 havingmale threading 646. Second section 640 engages with female threading 651in cavity 650 of third section 642, pulling post 628 in direction DR3into the locked position. In the locked position, flange 636 abuts thesurface of plate 620A preventing further displacement in direction DR4;second end 634 of first section 638 is completely seated in one of thethrough-bores of plurality of through-bores 622B which corresponds tothe chosen device height. In this locked position, device 600 isprevented from collapsing in direction DR2. Additionally, in the lockedposition, cylindrical portion 647 of fourth section 644 is completelyseated in one of the through-bores of plurality of through-bores 622F ofplate 620F; and, stopping element 648 abuts the outer surface of plate620F preventing further displacement of third section 642 and fourthsection 644 in direction DR3.

Device 600 further comprises post 652 (shown in FIGS. 34, 36, and 38).Post 652 is provided to secure locking mechanisms 614 and 618 inposition once device 600 is expanded to its final height. Post 652further comprises first section 662, second section 644, third section666, and fourth section 668. First section 662 includes first end 656,second end 658, and flange 660. First end 656 includes a recessoperatively arranged to engage with any device known in the art that canimpart rotational motion onto first section 662, e.g., a drill. Secondend 658 is non-rotatably secured to second section 664. Second section664 includes external helical male threading 670. Third section 666includes a substantially hollow shaft with cavity 674. Cavity 674includes internal helical female threading 675 operatively arranged toengage with male threading 670. Fourth section 668 includes cylindricalportion 671 non-rotatably secured to third section 666; and, stoppingelement 672 which is embodied as a substantially rectangular memberoperatively arranged to abut the surface of plate 620H and preventmovement of post 652 in direction DR3. Second section 664 has a diameterD1. Third section 666 has diameter D2 larger than D1. Cylindricalportion 671 of fourth section 668 has diameter D3 larger than D2, andstopping element 672 has diameter D4 larger than D3. Flange 660 hasdiameter D4 larger than D3.

After device 600 has been inserted into disc space 12 and expanded to anappropriate height, a surgeon can apply torque to first end 656 of firstsection 662. The torque is then transferred to second section 664 havingmale threading 670. Second section 664 engages with female threading 675in cavity 674 of third section 666, pulling post 652 in direction DR3into the locked position. In the locked position, flange 660 abuts thesurface of plate 620C preventing further displacement in direction DR4;second end 658 of first section 662 is completely seated in one of thethrough-bores of plurality of through-bores 622D which corresponds tothe chosen device height. In this locked position, device 600 isprevented from collapsing in direction DR2. Additionally, in the lockedposition, cylindrical portion 671 of fourth section 668 is completelyseated in one of the through-bores of plurality of through-bores 622H ofplate 620H; and, stopping element 672 abuts the outer surface of plate620F preventing further displacement of third section 642 and fourthsection 644 in direction DR3.

FIG. 39 is a partial front perspective view of a locking mechanism 720in an unlocked state. Locking mechanism 720 comprises plates 722 and724, and fastener 726. Plates 722 and 724 are fixedly secured tosuperior component 702 and inferior component 704 (discussed infra),respectively. Plate 722 includes plurality of catches 730 and plate 724includes through-bore 732. Through-bore 732 has female threading 734.Plurality of catches 730 is illustrated as a plurality of tapereddepressions having a taper back section and a flat ridge similar to aratchet mechanism which are arranged to prevent motion in one directionwhile allowing motion in a second direction. Fastener 726 includes firstend 740 and second end 742. Second end 742 has diameter D1 and includesmale threading 744 operatively arranged to engage with female threading734 of through-bore 732. First end 740 of fastener 726 has diameter D2larger than D1. First end 740 is operatively arranged to engage with anydevice known in the art that can impart rotational motion onto fastener726, e.g., a drill.

Each catch of plurality of catches 730 has a width greater than or equalto diameter D2.

Before locking, fastener 726 is loosely engaged with female threading734 of through-bore 732. During surgery, and after device 700 (discussedinfra) has been expanded to its final height, a surgeon impartsrotational motion to fastener 726. Male threading 744 of fastener 726further engages with female threading 734 of through-bore 732 whichpulls fastener 726 in direction DR4. When second end 742 of fastener 726is engaged with one of the catches of plurality of catches 730, device700 is locked and is prevented from collapsing in direction DR2. FIG. 40is a partial front perspective view of a locking mechanism 720 in alocked state. When device 700 is in the fully collapsed state plates 722and 724 nest within recesses 718.

FIG. 41 is a front perspective view of device 700 with lockingmechanisms 714 and 716, in an unexpanded state. Device 700 comprisessuperior component 702, inferior component 704, and expansion mechanism710 arranged to displace superior component 702 in a first direction DR1relative to inferior component 704. Superior component 702 and inferiorcomponent 704 further comprise at least one first aperture 706 and atleast one second aperture 708, which are arranged to allow fusionbetween bone fusing material and the adjacent vertebra.

Superior component 702 has a first surface 703 and inferior component704 has a first surface 705. Device 700 further comprises hinge 712fixedly secured to superior component 702 and inferior component 704 andarranged to rotatably displace the superior component about axis ofrotation AR. Locking mechanisms 714 and 716 are preferably lockingmechanism 720 described supra. Expansion mechanism 710 is preferablyexpansion mechanism 176 described supra. It should be noted that sinceplates 722 and 724 are fixedly secured to superior and inferiorcomponents 702 and 704, respectively, recesses 718 are provided withinwhich plates 722 and 724 can nest while device 700 is in a collapsedstate. It should further be appreciated that plates 722 and 724 can behingedly secured to superior component 702 and inferior component 704,respectively. FIG. 42 is a front perspective view of device 700 withlocking mechanisms 714 and 716 in an expanded state.

FIG. 43 is a partial front perspective view of a locking mechanism 820in an unlocked state. Locking mechanism 820 comprises plates 822 and824, and fastener 826. Plates 822 and 824 are fixedly secured tosuperior component 802 and inferior component 804 (discussed infra),respectively. Plate 822 includes plurality of catches 830 and plate 824includes through-bore 832. Through-bore 832 has female threading 834.Plurality of catches 830 are illustrated as a series of cylindricalpartial-through-bores. Fastener 826 includes first end 840 and secondend 842. Second end 842 has diameter D1 and includes male threading 844operatively arranged to engage with female threading 834 of through-bore832. First end 840 of fastener 826 has diameter D2 larger than D1. Firstend 840 is operatively arranged to engage with any device known in theart that can impart rotational motion onto fastener 826, e.g., a drill.Each catch of plurality of catches 830 has a width greater than or equalto diameter D2.

Before locking, fastener 826 is loosely engaged with female threading834 of through-bore 832. During surgery, and after device 800 (discussedinfra) has been expanded to its final height, a surgeon impartsrotational motion to fastener 826. Male threading 844 of fastener 826further engages with female threading 834 of through-bore 832 whichpulls fastener 826 in direction DR4. When second end 842 of fastener 826is engaged with one of the catches of plurality of catches 830, device800 is locked and is prevented from collapsing in direction DR2. FIG. 44is a partial front perspective view of a locking mechanism 820 in alocked state. When device 800 is in the fully collapsed state plates 822and 824 nest within recesses 818.

FIG. 45 is a front perspective view of device 800 with lockingmechanisms 814 and 816, in an unexpanded state. Device 800 comprisessuperior component 802, inferior component 804, and expansion mechanism810 arranged to displace superior component 802 in a first direction DR1relative to inferior component 804. Superior component 802 and inferiorcomponent 804 further comprise at least one first aperture 806 and atleast one second aperture 808, which are arranged to allow fusionbetween bone fusing material and the adjacent vertebra. Superiorcomponent 802 has a first surface 803 and inferior component 804 has afirst surface 805. Device 800 further comprises hinge 812 fixedlysecured to superior component 802 and inferior component 804 andarranged to rotatably displace the superior component about axis ofrotation AR. Locking mechanisms 814 and 816 are preferably lockingmechanism 820 described supra. Expansion mechanism 810 is preferablyexpansion mechanism 176 described supra. It should be noted that sinceplates 822 and 824 are fixedly secured to superior and inferiorcomponents 802 and 804, respectively, recesses 818 are provided withinwhich plates 822 and 824 can nest while device 800 is in a collapsedstate. It should further be appreciated that plates 822 and 824 can behingedly secured to superior component 802 and inferior component 804,respectively. FIG. 46 is a front perspective view of device 800 withlocking mechanisms 814 and 816 in an expanded state.

It will be appreciated that various aspects of the disclosure above andother features and functions, or alternatives thereof, may be desirablycombined into many other different systems or applications. Variouspresently unforeseen or unanticipated alternatives, modifications,variations, or improvements therein may be subsequently made by thoseskilled in the art which are also intended to be encompassed by thefollowing claims.

REFERENCE NUMERALS

-   10 Spinal column-   C1-C7 Cervical vertebrae-   T1-T9 Thoracic vertebrae-   L1-L5 Lumbar vertebrae-   S Sacrum-   C Coccyx-   D1 First diameter-   D2 Second diameter-   D3 Third diameter-   D4 Fourth diameter-   DR1 Direction-   DR2 Direction-   DR3 Direction-   DR4 Direction-   D_(L1-L2) Disc-   D_(L2-L3) Disc-   D_(L3-L4) Disc-   D_(L4-L5) Disc-   F Facet-   FJ Facet joint-   _(H1) Collapsed height-   _(H2) Expanded height-   SP Spinous process-   TP Transverse process-   IF Intervertebral foramen-   A Annulus-   AR Axis of rotation-   N Nucleus-   NC Neural canal-   H₁ Unexpanded height-   H₂ Expanded height-   RIM Rotational direction 1-   RD2 Rotational direction 2-   21 Disc space-   100 Device-   102 Superior component-   103 First surface-   104 Inferior component-   105 Second surface-   106 Expansion mechanism-   108 Expansion mechanism-   110 Expansion mechanism-   112 Locking mechanism-   114 Locking mechanism-   116 Locking mechanism-   118 Locking mechanism-   120A Plate-   120B Plate-   120C Plate-   120D Plate-   120E Plate-   120F Plate-   120G Plate-   120H Plate-   122A Through-bores-   122B Through-bores-   122C Through-bores-   122D Through-bores-   122E Through-bores-   122F Through-bores-   122G Through-bores-   122H Through-bores-   124 First aperture-   126 Second aperture-   128 Post-   130 Fastener-   132 First end-   134 Second end-   136 Female threading-   138 First section-   140 Second section-   142 Third section-   144 Fourth section-   146 Male threading-   148 Stopping element-   150 Longitudinal space-   152 Post-   154 Fastener-   156 First end-   158 Second end-   160 Female threading-   162 First section-   164 Second section-   166 Third section-   168 Fourth section-   170 Male threading-   172 Stopping element-   174 Longitudinal space-   176 Expansion mechanism-   178 Threaded rod-   180 Threaded sleeve-   182 Worm drive-   184 Worm-   186 Gear-   220 Locking mechanism-   222 Plate-   224 Pawl-   226 Biasing element-   228 Post-   230 Fastener-   232 First surface-   234 Second surface-   236 Corner-   238 Hinge-   240 Through-bore-   242 First plurality of teeth-   244 Second plurality of teeth-   246 Through-bore-   248 First pawl head-   250 Second pawl head-   252 Hinge-   254 First protrusion-   256 Second protrusion-   258 First end-   260 Second end-   262 Male threading-   264 Stopping element-   266 First end-   268 Second end-   270 Female threading-   200 Second embodiment-   202 Superior component-   203 First surface-   204 Inferior component-   205 Second surface-   206 First aperture-   208 Second Aperture-   210 Expansion mechanism-   212 Hinge-   214 Locking Mechanism-   216 Locking Mechanism-   320 Locking mechanism-   322 Plate-   324 Post-   326 Fastener-   328 Corner-   330 Hinge-   332 Plurality of through-bores-   334 Longitudinal space-   336 First end-   338 Second end-   340 Male threading-   342 Hinge-   344 First protrusion-   346 Second protrusion-   348 First end-   350 Second end-   352 Flange-   354 Female threading-   300 Device-   302 Superior component-   303 First surface-   304 Inferior component-   305 Second surface-   306 First aperture-   308 Second aperture-   310 Expansion mechanism-   312 Hinge-   314 Locking Mechanism-   316 Locking Mechanism-   420 Locking mechanism-   422 Plate-   424 Plate-   426 Post-   428 Fastener-   430 Plurality of through-bores-   432 Plurality of through-bores-   434 Longitudinal space-   436 Longitudinal space-   438 First end-   440 Second end-   442 Male threading-   444 Shoulder-   446 Stopping element-   448 First end-   450 Second end-   452 Female threading-   400 Device-   402 Superior component-   403 First surface-   404 Inferior component-   405 Second surface-   406 First aperture-   408 Second aperture-   410 Expansion mechanism-   412 Hinge-   414 Locking mechanism-   416 Locking mechanism-   418 Recess-   520 Locking mechanism-   522 Plate-   524 Plate-   526 Fastener-   530 Plurality of through-bores-   532 Plurality of through-bores-   534 Longitudinal space-   540 First end-   542 Second end-   544 Male threading-   500 device-   502 Superior component-   503 First surface-   504 Inferior component-   505 Second surface-   506 First aperture-   508 Second aperture-   510 Expansion mechanism-   512 Hinge-   514 Locking mechanism-   516 Locking mechanism-   518 Recess-   600 Device-   602 Superior component-   603 First surface-   604 Inferior component-   605 Second surface-   606 Expansion mechanism-   608 Expansion mechanism-   610 Expansion mechanism-   612 Locking mechanism-   614 Locking mechanism-   616 Locking mechanism-   618 Locking mechanism-   620A Plate-   620B Plate-   620C Plate-   620D Plate-   620E Plate-   620F Plate-   620G Plate-   620H Plate-   622A Through-bore-   622B Through-bores-   622C Through-bore-   622D Through-bores-   622E Square through-bore-   622F Through-bores-   622G Square through-bore-   622H Through-bores-   624 First aperture-   626 Second aperture-   628 Post-   630 Fastener-   632 First end-   634 Second end-   636 Flange-   638 First section-   640 Second section-   642 Third section-   644 Fourth section-   646 Male threading-   647 Cylindrical portion-   648 Stopping element-   650 Cavity-   651 Female threading-   652 Post-   654 Fastener-   656 First end-   658 Second end-   660 Flange-   662 First section-   664 Second section-   666 Third section-   668 Fourth section-   670 Male threading-   671 Cylindrical portion-   672 Stopping element-   674 Cavity-   675 Female threading-   720 Locking mechanism-   722 Plate-   724 Plate-   726 Fastener-   730 Plurality of catches-   732 Through-bore-   734 Female threading-   740 First end-   742 Second end-   744 Male threading-   700 Device-   702 Superior component-   703 First surface-   704 Inferior component-   705 Second surface-   706 First aperture-   708 Second aperture-   710 Expansion mechanism-   712 Hinge-   714 Locking mechanism-   716 Locking mechanism-   718 Recess-   820 Locking mechanism-   822 Plate-   824 Plate-   826 Fastener-   830 Plurality of catches-   832 Through-bore-   834 Female threading-   840 First end-   842 Second end-   844 Male threading-   800 Device-   802 Superior component-   803 First surface-   804 Inferior component-   805 Second surface-   806 First aperture-   808 Second aperture-   810 Expansion mechanism-   812 Hinge-   814 Locking mechanism-   816 Locking mechanism-   818 Recess

What is claimed is:
 1. A stand-alone expandable interbody spinal fusiondevice, comprising: a superior component; an inferior component; anexpansion mechanism operatively arranged to displace the superiorcomponent in a first direction relative to the inferior component abouta first hinge; and, a locking mechanism comprising: a plate operativelyarranged to pivot about a second hinge, the plate further comprising afirst through-bore and a first plurality of teeth; a pawl operativelyarranged to pivot about a third hinge, the pawl further comprising asecond through-bore; and, a post operatively arranged to pass throughthe second and third through-bores, wherein after the superior componentis displaced in the first direction, the locking mechanism preventsdisplacement of the superior component in a second direction, oppositethe first direction.
 2. The stand-alone expandable interbody spinalfusion device as recited in claim 1, further comprising a biasingelement operatively arranged between the pawl and the inferiorcomponent.
 3. The stand-alone expandable interbody spinal fusion deviceas recited in claim 1, wherein the second hinge is operatively arrangedon a first protrusion of the inferior component, and the third hinge isoperatively arranged on a second protrusion of the inferior component.4. The stand-alone expandable interbody spinal fusion device recited inclaim 1, wherein the plate further comprises a second plurality ofteeth.
 5. The stand-alone expandable interbody spinal fusion devicerecited in claim 4, wherein the plate has a first surface and a secondsurface, where the first plurality of teeth and the second plurality ofteeth are operatively arranged on the second surface of the plate. 6.The stand-alone expandable interbody spinal fusion device recited inclaim 5, wherein the pawl further comprises a first pawl head,operatively arranged to engage with the first plurality of teeth.
 7. Thestand-alone expandable interbody spinal fusion device recited in claim5, wherein the pawl further comprises a second pawl head, operativelyarranged to engage with the second plurality of teeth.
 8. Thestand-alone expandable interbody spinal fusion device recited in claim1, wherein the post further comprises a first end and a second end, thefirst end having a first threading operatively arranged to receive afastener and the second end having a stopping element.
 9. Thestand-alone expandable interbody spinal fusion device recited in claim1, wherein the biasing element is a flat spring.
 10. The stand-aloneexpandable interbody spinal fusion device of claim 1 wherein the platecomprises a plurality of through-bores, each of the plurality ofthrough-bores having a first diameter operatively arranged to receivethe first end of the post.
 11. The stand-alone expandable interbodyspinal fusion device recited in claim 10, wherein the plate furthercomprises a longitudinal slot arranged through the plurality ofthrough-bores of the plate, the longitudinal slot having a width lessthan the first diameter of the first plurality of through-bores.
 12. Astand-alone expandable interbody spinal fusion device, comprising: asuperior component; an inferior component; an expansion mechanismoperatively arranged to displace the superior component in a firstdirection relative to the inferior component about a hinge; and, alocking mechanism comprising: a first plate fixedly secured to thesuperior component, the first plate further comprising a first pluralityof through-bores; a second plate fixedly secured to the inferiorcomponent, the second plate further comprising a second plurality ofthrough-bores; a post having a first end and a second end, wherein afterthe superior component is displaced in the first direction, the lockingmechanism prevents displacement of the superior component in a seconddirection, opposite the first direction.
 13. The stand-alone expandableinterbody spinal fusion device recited in claim 11, wherein the firstand second plates are operatively arranged to slide past each other suchthat the first and second pluralities of through-bores are aligned. 14.The stand-alone expandable interbody spinal fusion device recited inclaim 11, wherein the post further comprises a first section having afirst diameter, and a second section having a second diameter, largerthan the first diameter.
 15. The stand-alone expandable interbody spinalfusion device of claim 11 wherein the first end of the post has a firstthread operatively arranged to receive a fastener and the second end hasa stopping element.
 16. The stand-alone expandable interbody spinalfusion device of claim 11 wherein the second plurality of through-boreshas a first diameter and are arranged to receive a first end of afastener, and the first plurality of through-bores have a seconddiameter less than the first diameter and are arranged to receive asecond end of the fastener.
 17. A stand-alone expandable interbodyspinal fusion device, comprising: a superior component; an inferiorcomponent; an expansion mechanism operatively arranged to displace thesuperior component in a first direction relative to the inferiorcomponent; and, a locking mechanism comprising: a first plate fixedlysecured to the superior component, the first plate further comprising afirst plurality of through-bores; a second plate fixedly secured to theinferior component, the second plate further comprising a secondplurality through-bores; a third plate fixedly secured to the superiorcomponent, the third plate further comprising a third plurality ofthrough-bores; a fourth plate fixedly secured to the inferior component,the fourth plate further comprising a fourth plurality of through-bores;and, a post having a first end and a second end, the post arranged toengage with the first through-bore, the second through-bore, the thirdthrough-bore, and the fourth plurality through-bores, wherein after thesuperior component is displaced in the first direction, the lockingmechanism prevents displacement of the superior component in a seconddirection, opposite the first direction.
 18. The stand-alone expandableinterbody spinal fusion device recited in claim 17, wherein the firstand second plates are operatively arranged to slide past each other suchthat the first and second pluralities of through-bores are aligned. 19.The stand-alone expandable interbody spinal fusion device recited inclaim 17, wherein the third and fourth plates are operatively arrangedto slide part each other such that the third and fourth pluralities ofthrough-bores are aligned.
 20. The stand-alone expandable interbodyspinal fusion device recited in claim 17, wherein the post furthercomprises a first section, a second section, a third section, and afourth section, the first and third sections having a first diameter,and the second and fourth sections having a second diameter larger thanthe first diameter.
 21. The stand-alone expandable interbody spinalfusion device recited in claim 17, wherein the first end of the post hasa first thread operatively arranged to receive a fastener and the secondend has a stopping element.
 22. The stand-alone expandable interbodyspinal fusion device recited in claim 17, wherein the post furthercomprises a first section, a second section, a third section, and afourth section, the first section comprising a flange, the secondsection comprising a first thread, the third section comprising atubular member having a cavity with a second thread operatively arrangedto engage with the first thread, and the fourth section comprising astopping element.
 22. A stand-alone expandable interbody spinal fusiondevice, comprising: a superior component; an inferior component; anexpansion mechanism operatively arranged to displace the superiorcomponent in a first direction relative to the inferior component; and,a locking mechanism comprising: a first plate fixedly secured to thesuperior component, the first plate further comprising a first pluralityof catches; a second plate fixedly secured to the inferior component,the second plate further comprising a through-bore; and, a fastenerarranged to engage with the through-bore and one catch of the pluralityof catches, wherein after the superior component is displaced in thefirst direction, the locking mechanism prevents displacement of thesuperior component in a second direction, opposite the first direction.23. The stand-alone expandable interbody spinal fusion device recited inclaim 22, wherein the plurality of catches is includes a plurality ofpartial through-bores.
 24. The stand-alone expandable interbody spinalfusion device recited in claim 22, wherein the plurality of catches isincludes a plurality of tapered depressions.